2001 ford taurus running rough at low rpm

car at low rpm or at cruising speed has a stutter or flutter feel as if trying to shift. it has been on diagnostic machine and no problems were found. ford shop put in new plugs and wires but problem persists and even seems to be getting worse. problem is very subtle and car is driven daily with no problems, however i am concerned about transmission or torque converter causing these rough spots and will car remain dependable?car has 92000 miles and has been well maintained. thank you for your time Doug Privitt

in addition to above mentioned details, there is also a metalic noise as if something is loose and vibrating in front of car. especially noticed at low speeds and at idle, mostly idling in gear. this is a vibrating sound and not a feel.

Do you know if your ignition coil was tested when the new plugs and wires were put in? If not I would have it checked along with the throttle position sensor.

The metallic vibration is likely the heat shield for your exhaust manifold. You can probably verify that by popping the hood and looking/listening while someone works the accelerator (or work throttle by hand) - car in park w/ parking brake set, of course! Also, if the car is hot don’t go sticking your hands in there.